not so innocent

On a photo shoot of a company picnic. I had to take pictures of kids.
One would think, that this sweet little sad looking kid is innocent.
"Kid's giving me the bird"
ISO 1600 shot in side hand held, no flash, soft focus effect used.

But when his face LOOKS so sad and suggesting innocence, why do you say "not so innocent"? What do you know about the whole context in which you took this photo that the normal viewer (like myself) doesn't know?